Electric circuit control apparatus



2 Sheets-Sheet l Oct. 6, 1936. F. D. AUSTIN ELECTRIC CIRCUIT CONTROL APPARATUS Original Filed Aug. 27, 1932 066 6,11936. FQ D. Ausw 2,056,760

ELECTRIC CIRCUIT CONTROL APPARATUS Original Filed Aug. 27, 1952 2 Sheets-Sheet 2 gmuntoz:

FRI-:Damm D AUNIL Patented Oct. 6, 1936 UNITED STATES PATENT GFFICE Application August 27,

1932, Serial No. 630,742

Renewed August 13, 1935 30 Claims.

This invention relates to improvements in the art of controlling electrical circuits destined to govern the conditions of heat transference apparatus, such as domestic boilers,

and other furnace and boiler construction for insuring safety at all times and preventing overheating or dangerous water level drop or other untoward or undesirable conditions.

Among the objects in view is the provision of a highly sensitive control responsive to furnace or boiler conditions for governing the operation thereof accordingly.

A further object is the effective avoidance of failure of the safety controlling apparatus tol F function as intended.

In greater detail, a further object is to insure the making or breaking of a circuit or circuits as and when required under conditions of highly sensitive responsiveness of the circuit making and breaking means.

With these and further objects in View as will in part hereinafter become apparent and in part be stated, the present improved invention includes a heat-responsive unit for controlling a circuit, and also includes a fusing alloy which is heat-responsive and proportioned for a relatively high degree of responsiveness for fusing at substantially uniform, predetermined temperatures.

The invention further includes heat-responsive control means for a plurality of circuits for breaking and making circuits under excess heat conditions.

The invention also includes certain other novel constructions, combinations, and arrangements of parts as will subsequently become apparent and will thereafter be pointed out in the appended claims.

In the accompanying drawings- Figure l is a View partly in side elevation and partly in longitudinal section of an embodiment of the heat-responsive unit and cooperating parts shown detached, parts being broken away and seen in section for disclosing interior parts in elevation.

Figure 2 is a fragmentary perspective view of the immediate heat-responsive unit with a diagrammatic showing of its circuit, the fuse being in its circuit-closing condition.

Figure 3 is a similar View of the same with the fuse in the circuit-breaking condition, the circuit being omitted.

Figure 4 is a similar view of a slightly modified embodiment with the circuit shown dial grammatically.

Figure 5 is a View similar to Figure 2 of a multiple circuit heat-responsive unit With thc circuit shown diagrammatically.

Figure 6 is a transverse section therethrough taken on the plane indicated by line 6--6 of Figure 5.

Figure 7 is a View similar to Figure 4 of a slightly modified form of circuit closer, the circuit being omitted.

Figure 8 is a View similar to Figure 7 of a modified embodiment thereof to provide for multiple circuits, the circuits being seen diagrammatically.

Figure 9 is a vieW similar to Figure 8 of a further slight modification, the circuits being omitted.

Referring to the drawings by numerals, l indicates a standard electric fitting consisting of a pronged insulating carrier having a rightangle armor shield 2iv to receive any of the well known armored electric cables with multiple Wires. The prongs of the fitting I are remor ably inserted in an insulating handle 3, which is provided with the customary sockets for receiving the prongs from the part l and directing them into contact with the outer terminals of electrical conductors 4, 4. The conductors 4 extend throughout the length of an insulating bar or rod 5 Which extends from the end of and is preferably formed integral with the handle 3, the outer end of the rod adjacent the handle being provided with threads S for being detachably threaded into a metallic shell or casing l. The shell 'l at its outer end is preferably provided with a nut-like or polysided handle 3 adapted to receive a Wrench or other tool for rotating the shell into operative position. The shell is provided with threads 9 adjacent the handle 8, Which threads are preferably of the pipe thread type so as to be properly received in any appropriate pipe coupling or tting. The shell 'l is preferably, as seen in Figure 1, imperforate and closed at its inner end so as to prevent moisture from reaching the contained parts when the shell 'l is surrounded by moisture. The outer end portion of the shell is internally threaded to receive the thread 6 of the bar 5. The conductors 4 are preferably in theform of rods of resilient material so as to be capable of being sprung toward each other as seen in Figure 1. The bar 5 is provided With enlargements l0, l0 of the passageways through which the rods 4 extend at least for a short length of the inner prise the contact members of rods 4, 4 and areV held in conducting relation by the material I3.

Each of the plates I2 is provided with a sleeve i4 to receive the respective terminals of rods 4 and the sleeves are shaped to snugly receive the flattened terminals II and thus prevent the plates I2 from rocking or pivoting on the rods i when the fuse I 3 gives way and allows the parts to move apart under the expanding tension of the rods 4 to the position seen in Figure 3.

The plates I2 are preferably made of relatively thin sheet metal, such as copper, and the fusing material I3 is preferably as thin as is practicable for resisting fusing under heat up to the degree previously determined, and,l to that end, the film of fusing material i3 is preferably in the nature of solder applied as a thin solder coat between the two sheets I2.

While the heat-responsive unit or fuse, as seen in Figures 1 and 2, is capable of a Wide range of use, one effective use is indicated by the diagrammatically shown hookup as seen in Figure 2, wherein one of the conductors or rods 4 is connected by a line I5 directly to one side I6 of the source of current, and the other rod 4 is connected by a line I'I through the instrumentality to be actuated I8 with the other side, of the source of current indicated at I9. The instrumentality to be actuated may, for pur'- poses of illustration, comprise the operating motor of an oil burner, or any other motor controlling the supply of fuel to the furnace or other heat transference apparatus which is being safeguarded by the heat-responsive unit.

It will be observed that as long as conditions remain normal and satisfactory, and the boiler or other heat transference apparatus is operating under safe conditions, the current will flow through the fuse I3 uninterruptedly. However, if from a drop in the water level below the safety level or from any other cause the fusing material I3 becomes overheated, the melting of that material will release the plates I2 from their connection with each other and the parts will-move quickly apart under the spring action of the rods 4 to the position indicated in Figure 3. Assuming the line I6 to be the hot side and line i8 to be grounded, the current can not pass from E5 to line I9, and, therefore, the motor I8 will cease operating and prevent maintenance or increase in the dangerous condition. An insulating sleeve 20 preferably surrounds the heatresponsive unit so that, when the rods V4 move apart incident to the fusing of the fuse material I 3, no part of the plates can reach contact with the shell l. The sleeve 23 is preferably detachably slid over the inner end portion of the rod 5, but may be otherwise arranged within the inner portion of shell l so long as the heatresponsive unit is properly safeguarded. It will also be observed that when the plates I2 have moved apart incident to the release of the fuse i3, they can not rock or tilt or otherwise pivot, and, therefore, can not by assuming a diagonal position accidentally come in contact with each other.

The shell and its contained parts are, of course, Well adapted for use anywhere where the rise of temperature beyond a predetermined point indicates a dangerous condition and may be depended upon to effect release of the fuse. One important location is,that of having the shell extending into the water of a boiler so that, when the liquid level drops too low, the shell is exposed directly to the heat action, and, therefore, to such a temperature as will break the circuit of the fuel supply apparatus, and thus prevent continuation of the overheating or the dangerous condition incident to a too low Water level. It should be understood, of course, that the lines I5 and II extend through the standard connection 2 and thus are detachably maintained in electrical contact respectively with the conductors or rods 4.

As a special application, the shell 1 may be threaded into the outer threaded end. of an adapter 2I having a lower connection 22 With the boiler` below the liquid level thereof and an upper connection 23 with the boiler above the normal liquid level, the adapter 2| being located at approximately the lowest safe liquid level. It is also feasible to arrange the adapter 2| to extend into the flue or other heat travel area of the furnace or other heat transference apparatus, and, to that end, clamping nuts 24, 24, may be threaded onto the extended portion of the adapter 2I for clamping the parts in the desired location.' Details of the preferable arrangement and connection of the adapter 2| are seen in my co-pending patent application filed even date herewith.

It is well understood, of course, that with various heat transference apparatus and various types of fuel and forms of fuel feeding and controlling devices, diierent circuit hook-ups are required, according to the nature of the action necessary. For instance, while the foregoing has been applied directly to a motor circuit wherein the action of the motor is depended upon for supplying fuel, it is entirely practicable to apply the present invention to motor circuits where the motor is depended upon to cut off the supply of fuel, as,rfor instance, Where a motor is employed to close a gas Valve. Or, under some circumstances, it may become desirable to have an alarm set off with the arising of a dangerous condition. Y

In Figure 4 is illustrated an embodiment in which the circuit is controlled by being turned on or made instead of being brokenor turned off when the fuse is melted. In this form, the electric conductor members or rods 4a and 4b are supported or mounted in longitudinal bores through an insulating member or rod in the same manner as are the rods 4 of Fig. l. However, the rods Ia and 4b in addi tion to serving as current carrying members also comprise supporting or carrier elements or members. The free end portions IIa, IIb respectively of rods 4a, 4b function solely as supporting means and are not in circuit. The portion IIa is provided With an insulator or dielectric covering 25 preferably in the form of a sleeve or tube of insulating material which snugly ts and conforms to the portion Ila. The fuse 25a is of similar construction to that of Figs. 1, 2, and 3 and its parts are therefore designated by like reference characters, although as will be noted, the plates I2, I2 do not here comprise contact members. The rods 4a and 4b are held in fixed relation to each other by the fuse 254, one fuse sleeve I4 receiving the supporting rod portion IIb and the other fuse sleeve I4 receiving the insulated supporting rod portion IIa. The insulation 25 may be of any preferred kind, such as a layer of ber, or the rod 4a may be shortened and supplied with an extending end portion of insulating material adapted to enter the sleeve I4. The other rod 4b opposite that provided With the insulation 25 carries a contact member which may be in the form of a metal ring 28 which is fixed to and in electrical contact with the respective rod 4b and which is in surrounding spaced relation to the rod 4a which has the insulating material 25. The rods 4a and 4b are sprung or stressed toward each other when the heat-responsive unit or fuse 25a is slid into place on the rods, so that the heat-responsive unit retains the rods under tension, with the contact member 26 in spaced relation to its cooperable and engageable contact portion 26a on rod 4a which denes the other contact member. Thus, when the heat reaches the predetermined high degree, the fusible material I3 will disrupt and allow the plates I2 to spring apart as above described under the inherent resilient force of rods 4a and 4b. With that movement the ring 26 and the contact portion 26a of insulator carrying rod 4a will be brought into contact. As seen in Figure 4, one hookup with the construction just described may Well consist of a line 21 leading from a source of current to the conductor 4a carrying the insulation 25. A line 28 leads to the motor 29 for actuating the fuel valve or for operating an alarm, or other purpose as required, and a line 30 leads from the motor 29 back to the source of current. Thus, so long as the ring 26 is out of contact with portion 28a of the insulator carrying rod 4a, the motor 29 will remain stationary, but when the temperature rises to the danger point and the fuse 25a gives way, the operation of the rods 4a and 4b closing the circuit through the engaged contact members 26 and 26a will energize the motor 29 and accomplish the desired end.

While the heat-responsive or fuse members thus far described are designed for use in twowire circuits, the invention is well adapted for multiple circuit use, as seen in Figures 5 and 6, wherein the heat-responsive or fuse member consists of plates 3|, 3|, similar in all respects to the plates I2 and connected together by the fusing material 32. Plates 3| are provided with anchoring sleeves 33 adapted to receive the flattened terminal portions 34, 34, of conductor rods 35 and 36 corresponding to rods 4. But in this construction a third sleeve is provided, as indicated at 3l, and carrying and forming part of a plate or wings 38 spaced above and in line with one ofthe plates 3|. The sleeve 3l and plates 3| are thus normally out of electrical contact. A third conductor rod 39 having a attened portion 48 extends into and is in electrical contact with the sleeve 31 and holds the sleeve and plate 38 from tilting or otherwise moving under normal conditions so as to be sure not to contact with fuse plate 3|. While the parts of Figure 5, so far as the circuit is concerned, are shown diagrammatically, it will be readily understood that the rod 39in the actual physical embodiment will be embedded in the insulating rod or bar corresponding to bar 5 and held rigidly thereby, and the line from the conductor rod 39 will comprise a third wire of a three-wire circuit hook-up through the connection 2. While the three-wire circuit is capable of quite a wide range of variable hook-ups, one acceptable form is illustrated in Figure 5 in which 4| and 42 are the main line or supply wires, and it may be assumed that 4| is the hot Wire While 42 is the grounded wire. A bell-ringing or other transformer 43 is preferably hooked directly across the leads 4| and 42. A line 44 extends from lead 4| to the usual thermostat 45, and a line 46 extends from the thermostat to the rod 36. A line 41 leads from the rod 35 through the instrument to be energized, such as the oil burner motor 48, back to the lead 42. The second Winding of the transformer 42 has one side connected by line 49 to any appropriate signal or alarm 50, and a line 5I leads from the other side of the signal 58 to the line 44. A line 52 leads from the rod 39 to the side of the winding of the transformer opposite that connected to line 49.

With this particular multiple circuit hook-up, the operation will be apparent from the diagram seen in Figure 5, and consists of the continuous operation of the motor 48 when the thermostat 45 is in the closed position and other conditions are normal. Current from lead 4| ows along line 44, through the thermostat and line 46, through rod 36, plates 3| and the fuse 32, rod 35, line 4l, and thus back to the lead 42 through the motor 48. Should the heat for any reason reach the danger point and the fuse 32 be thereby fused, the rods 35 and 36 will spring apart and thus break the circuit to the motor 48. The upper plate 3| and sleeve 33 will spring upward when thus released, Since rod 35 is under spring tension. Sleeve 33 will be thus moved into contact with the wings of plate 38, and the circuit of signal 50 thus closed. The current from transformer 43 will then flow through the circuit 49, 5|, 44 to thermostat 45, 46 through rod 36, upper plate 3|, plate 38, and sleeve 3l, rod 39, and liner 52 back` to the transformer. The signal or alarm willy be thus given, and the hook-up is such that it will be given only when the motor is stopped by the dangerous condition producing response in the heat-responsive unit causing fusing of fuse 32.

In Figure 7 is seen a further embodiment substantially identical in form and operativeness to that seen in Figure 4, and differing essentially in details of construction. In the embodiment of Figure '7, the conductor rods 4, 4, are arranged exactly as seen in Figure 4 with the ring 28 carried by one of the rods 4 and surrounding but spaced from the other so long as the rods are held sprung toward each other by their engagement with the heat-responsive fusing unit consisting of the plate 53 soldered at 54 with the fusing solder to plate 55. Plate 55 is anchored to an insulating block 5B, as by a dovetail joint connection, the plate 54 being formed with inturned flanges to provide the necessary undercut groove for receiving the overhang piece of the block 55, so that the block can be readily slid into locking engagement with the plate. The block 56 is preferably formed with a flattened or polysided opening 51 for receiving the similarly shaped terminal portion of the respective rod 4, and the plate 35 is provided with the usual integral sleeve 5S to receive the polysided terminal portion of the other rod 4. The heatresponsive unit, as seen in Figure 7, is thus functionally identical with that seen in Figure 4, and its operation therefore does not require description.

In Figure 8 is seen a heat-responsive fusing unit similar generallyV in construction to that seen in Figure 7, but having the third connection corresponding to the embodiment seen in Figure 5, and, in fact, the fusing unit of Figure 8 and that of Figure 5 are obviously interchangeable. However, the hook-up shown in Figure 8 is somewhat different, and it must be understood that the present invention does not 'relate particularly to the hook-up but more directly to the means which makes the hook-up possible, and includes the fusing unit and itscooperating parts.

In Figure 8 is seen the plate 59 having the usual conductor receiving sleeve 60 vand secured by the fusing material 6| to the plate 62. A loop or band B3 extends laterally from the plate 62 and preferably surrounds an insulating block 64, the band terminating in a conductor-receiving, elongated sleeve 65. The insulating block 66 is provided with a conductor-receiving passageway or opening 66, which is preferably elongated or otherwise polysided in cross section and is adapted to receive the flattened end of a conductor rod. Conducto-r rods 61, 68, and 69 extend into the sleeve 65, the opening 66, and sleeve 69 respectively. A metal ring or other appropriate contact piece 'i9 is in electrical contact with and xed to the rod 68 and surrounds but is normally out of contact with rod 69. In this connection, it should be borne in mind that the ring 'ill andthe ring 25 while effective for the purposes indicated may perform their work also effectively even if they are not made in the form of a complete ring, but only so much is provided as will form a hook or part overhanging the non-conducting rod so as to come in Contact when the rods move apart.

While the hook-up of the structure seen in Figure 8 may be identically the same as that seen in Figure 5, or may be any other known multiple circuit hook-up, an acceptable arrangement is shown diagrammatically inFigure 8 to consist of a line H leading from the source of supply to the conductor 69, thence through plate 59, fusing material 6l, plate 62, and sleeve to conductor 6l'. A line I2 leads from conductor 61 back to the other side of the source of current through the motor or other electrically actuated part 13. Hence, so long as the fuse Sl remains intact, the motor 'H3 will function properly. When, however, the fuse 6I gives way and the plates 59 and 92 move apart, the rod 59 will come in Contact with the Contact making member I9 and thus the circuit will be changed, cutting out the motor 'I3 and establishing a circuit from the source of supply through line 1I, conductor 69, ring 10, conductor 68, and line 18 to transformer l5, and thence by line I3 back tothe source of current. The transformer may be connected to any part to be energized, such as the alarm Tl.

In Figure 9 is seen a very slight modification of the construction shown in Figure 8 in which the essential difference is the employment of a narrower band about the insulating block, so that the dovetail connection, as seen in Figure 7, may be effectively employed, and as the description of Figure 8 with the exception mentioned equally applies to Figure 9, the same reference numerals have been employed and repetition of the description is unnecessary.

As will be apparent from the foregoing and from the drawings, each of the heat-responsive units is made up in a manner to enable it to be slid onto and off of or have slip engagement with the respective flattened or polysided end portions ofA the conductor rods. Thus, after a fuse has blown the operator withdraws the coupling I and unscrews the rod 5 and withdraws it from the shell '1. It will be noted that the shell 1 remains in place so that there is no leakage of water from the adapter 2|. If the sleeve 29 is mounted on the rod 5, it is withdrawn and then the respective disconnected parts of the fuse unit are slid off of the conductor rods and a new fuse unit slid onto the rods. Naturally, the rods are relatively sprung toward each other to enable the new fuse unit to be slid into place so that the required tension will be provided to cause separation of the parts of the unit when fusing occurs. When the hook-up includes the rod 39 or the rod 61 or the third rod in any instance, it is not necessary to put the third rod under tension, but only to provide relative tension between the two other rods.

While the present invention is shown in the drawings and above described as especially well adapted for use in connection with boilers and like heat-transference apparatus, it should be understood that the control or heat-responsive unit is just as effectively designed and adapted for many other uses. In Figure 1 of the drawings, the parts are shown on a scale which for boiler application is approximately normal and standard, and, of course, the other figures show the parts on exaggerated scales for average uses; but the invention is in no sense limited to size or proportions of parts so long as the operative combinations are maintained, and the parts may be made larger or smaller than shown according to the use or application desired.

For instance, among many other valuable uses additional to those above set forth, the parts may be proportioned (usually reduced in size) to adapt the heat-responsive unit and one or more of its circuits to be successfully employed in conjunction with bearings or other mechanical parts where friction endangers disastrous heating in the absence of adequate lubricant. The bearings for rotating, oscillating and reciprocating shafts and other moving parts are universally lubricated to reduce friction, and the lubricant in reducing the friction avoids development of heat; but it not infrequently happens that through clogging of oil ducts or otherwise a dearth of lubricant occurs and the bearing is burned out or other parts injured. The present invention is particularly well adapted and especially designed to prevent such injury. The friction-produced heat causes the fuse to respond and cut out or otherwise govern the current on which the machinery depends for its operation. and. therefore. before the friction has done anv damage. the movement of the insuifciently lubricated part is stopped. and the bearing is saved. To apply the invention to a bearing, the parts are, of course, made of a size to cooperate with the particular bearing, and an opening or pocket is formed in the bearing part or a cooperating or adjacent part, and the Wall of such opening is tapped so that the thread 6 can be caused to thread into the opening until the fuse I3 is in sufficient proximity to the bearing or part that will be likely to be heated by friction to insure fusing of the fuse before any injury has been Tsi very thin lm of the fusing solder.

done. f course, the shell 'l will not be used in such an arrangement, but an electrical insulator, such as sleeve will be used, or any appropriate insulating cover for the conductor 7 parts will be provided to prevent short-circuiting.

The sleeve 5' or other insulator cover will, of course, be located as near to the part to be protected as possible short of frictional contact so as to insure the highest possible degree of sensitiveness and responsiveness of the fuse to the heat as it begins to be generated by friction. Actual tests and continued use of the invention for safeguarding bearings has abundantly proved its success and eiciency. The burning out of a bearing, whether of the ponderous size of bearing for ships drive shafts or the smaller sizes, such as the connecting rod bearings of internal combustion engines, will be effectively avoided by the use of the present invention.

Obviously, numerous other uses are available for the invention, and it is valuable for safety and protection wherever any excessive or unintended heating occurs or other heat-transference happens resulting from an unintended, harmful or dangerous condition, and it is not a departure to apply the invention wherever usable.

It should also be understood that the heatresponsive control of the present invention will function effectively regardless of the source of the heat, whether generated, released, or accumulated, and the sensitiveness and durability of the fusing solder are of particular importance. By sensitiveness is meant capacity to respond or fuse at substantially the exact temperature required. It is customary for me to calculate on a variation of from three degrees above to three, degrees below the exact temperature point at which fusion is intended to occur, and this I consider a reasonable margin of safety, but from almost innumerable tests and actual commercial use I have successfully demonstrated that the variation will be much slighter under all ordinary conditions than this margin of safety.

The fusing material employed to provide the fuses I3, 32, 54, and 6| may for the technical interpretation and application of those parts of the invention not specifically relating to the fuse material itself be considered as any known fusing substance responding at the required temperatures. However, the fact is that the known fusing materials have not been satisfactory for regular use because submergence for any continued periods with known fusing material tends to vary the condition of the fusing material such that it can not be depended upon to fuse at any fixed temperature or within available variations therefrom, and among other objects of that part of the present invention which relates specifically to the fusing material itself is the production of a'fusing material capable of withstanding the action incident to submergence for long periods so as to constantly remain responsive to and fusible'at a substantially fixed temperature or within available variation therefrom, say not more than three degrees above or three degrees below the established or fixed kpoint of temperature. I find by many tests that the present improved fusing material will usually respond at practically identically the temperature required. This new fusing material which I have invented is comprised of an alloy of bismuth, lead, and tin proportioned to produce a solder adapted for soldering the plates together with a The proportions of bismuth, lead, and tin relative to each other is, of course, Varied according to the fusing point required. If the fusing point in hot Water is to be 212 F., the fusing alloy is produced by first making an initial alloy of fifty-eight parts bismuth to forty-two parts lead by weight, and then to this initial alloy are added five and twotenths parts of tin by weight. For an alloy which fuses at 222o F. after standing in hot water under pressure or vapor the initial alloy of iLy-eightr parts bismuth to forty-two parts lead by weight has added three and twenty-ve hundredths parts tin by weight. For an alloy which fuses at 240 F. after standing in hot water, as, for instance, Water under pressure of nine and onehalf pounds steam, the initial alloy of fifty-eight parts bismuth and forty-two parts lead by weight has added one and two-tenths parts tin by weight. For an alloy which fuses at 266 F. after standing in hot water, as, for instance, water under pressure of twenty-five pounds steam, an initial alloy is prepared of sixty-three parts tin to thirty-seven parts lead by weight, and to this initial alloy is added nine and two-tenths parts bismuth by weight. For an alloy which fuses at 298 F. after standing in hot water, as, for instance, water under pressure of fifty pounds steam, to the initial alloy of sixty-three parts tin and thirty-seven parts lead by weight are added five parts bismuth by weight. For an alloy which fuses at 322 F. after standing in hot water, as, for instance, water under pressure of seventy-five pounds steam, to the initial alloy of sixty-three parts tin and thirty-seven parts lead by weight are added three and two-tenths parts bismuth by weight. For an alloy which fuses at 338 F. after standing in hot water, as, for instance, water under pressure of one hundred pounds steam, to the initial alloy of sixty-three parts tin and thirty-seven parts lead by weight are added two parts bismuth by weight.

While I have referred to the fact that the fusing alloy thus produced is highly responsive at the predetermined or substantially predetermined temperature even though standing in water or other moisture, it should be understood that acting as a fuse this alloy in its various proportions named is effective also when subjected to various gases or left in the open air, so that it is highly dependable for fusing purposes at required, established temperatures.

This improved material is made the subject of my co-pending divisional application led April 19, 1933, Serial No. 666,931, since continued in part by my substitute co-pending application led May 4, 1934, Serial No. 723,997, correcting certain errors in the said divisional application; and the pipe fitting or tubular structure into which the thread 9 is shown as threaded in Figure 1, and also the combination thereof with the shell 'l and its contained parts are made the subject matter of claim in my co-pending application led August 27, 1932, Serial No. 630,743.

What is claimed is:

1. In circuit control apparatus, a fuse device cooperable with and operable to hold electric contact members in relatively fixed relation and comprising plates, means preventing tilting of the plates relative to each other when the plates are disconnected, and fusible material connecting the plates in facewise engagement.

2. In circuit control apparatus, conductor rods, a fuse device cooperable with said rods and comprising plates, said rods and said plates having'cooperable means to hold said plates against tilting relative to each other when said plates are disconnected and for assuring non-turning of said plates relative to said rods, and fusible material connecting said plates in facewise engagement.

3. In circuit control apparatus, conductor rods, one of said rods being under tension tending to move said rods relative to each other, a fuse device cooperable with and holding said rods in Xed relation to each other and comprising plates, said rods and said plates having cooperable means to hold said plates against tilting relative to each other when said plates are disconnected and for assuring non-turning of said plates relative to said rods, and fusible material connecting said plates in facewise engagement. Y

4. A fuse device comprising plates and fusible material connecting the plates, each of said plates being provided with a sleeve for detachably engaging a supporting member for the device. Y

5. A fuse device comprising plates and fusible material connecting the plates, the plates being provided with polysided sleeves adapted to have sliding, non-rocking engagement with supporting members.

6. A fuse device as claimed in claim 1 wherein the plates are flat.

7. A fuse device comprising plates and fusible material connecting the plates, the plates being formed into laterally outstanding supporting member receiving sleeves.

8. In circuit control apparatus, the combination of fuse-connected plates having means of detachable engagement with supporting rods, and means for insulating the engagement of one of the rods with one of the plates.

9. The combination as claimed in claim 8 wherein the means of engagement comprises sleeves, and the insulating means an insulating lining for one of the sleeves.

10. In circuit control apparatus, the combination, with an insulating bar, of conductor rods carried thereby, one of said rods being resilient and movable relative to the other, and the rods extending beyond the insulating bar, and metal plates slidingly engaging said rods, and fusible means connecting said plates.

ll. In circuit control apparatus, the combination, with conductor rods, one of which is tensioned to spring relative to the other, of a fuse unit engaging the rods and retaining the tensioned rod under tension, means insulating one of the rods from the fuse unit, and circuitmaking means carried by onerod and extending past the other and shaped to overhang the latter rod for effecting circuit-closing contact when the rods move relatively apart on being released by the fusion of the fuse unit.

12. In circuit control apparatus, a fuse device comprising fuse-connected plates, each having means of engagement with a conductor rod, and a second means of engagement with a conductor rod electrically connected with one of the plates.

13. A fuse device as claimed in claim 12 and insulating means for one of the conductor engaging means.

14. A fuse device as claimed in claim 12 in 4combination with conductor rods and circuitclosing means carried by one of the rods and located to contact with another rod upon the( fusing of the fuse means.

15. In circuit-control apparatus as claimed in claim 8 in combination with supporting rods engaging the same and a circuit closer carried by the non-insulated rod in position to contact with the insulated rod upon fusing of the fuse means.

16. The-combination as claimed in claim 1l wherein the circuit-making means is a ring fixed to one rod and surrounding the other and spaced therefrom While the rods are held by the fusing unit.

17. A fuse device as claimed in claim 12 wherein the means of engagement with the conductor rod in each instance is a receiving sleeve.

18. In circuit control apparatus, a fuse device comprising a plate adapted to detachably engage a conductor, fusible material on one face of the plate for affording electrical connection of the plate with another conductor, and a sleevelike part carrying the plate and adapted for engaging a suiiicient polysided portion of the rst-mentioned conductor to prevent tilting of the plate relative to said first-mentioned conductor.

19. In circuit control apparatus, a fuse device` plate thereto and retain the plate against tilting `movement Yrelative `tothe supporting member. .y v

21. In circuit control apparatus, a fuse device comprising a plate having@ poli/ Sidedv reevng portion, a supporting member shaped` .correspondingly to said portion and removably receiving said'device, said memberhavinga current conducting portion,A a current conducting member cooperable with said conducting portion to control an electric circuit. and fusible material anchoring said plate in position to retain said conducting portion in fixed .relation to said conducting member. c

. 22. In circuit control apparatus, a fuse device comprising a plate having a polysided receiving portion, a supporting member shaped correspondingly to said portion and removably receiving said device, said member having'a, current conducting portion, a current conducting member cooperable with said conducting portion to controlan electric circuit, and fusible material anchoring said plate in position to retain' said conducting p0rtion in xed relatori-.to said conductingmember, said supporting member being resilient and being held in said xed relation under stress such that said conducting portion Yismovable relative to said conducting member upon fusing .of said fusible material. Y f

`23. Inl circuit control" apparatus, the combination, with electrical conductors adapted to be held inV circuit closing relation Irelativevto each other and one movable withrespect to the other, of a plate detachablyand slidin'gly engaging one of the conductors, and fusingmaterial connecting the plate for retaining th'e movable conductor against movement to a circuit breaking relation with respect tothe otherjconductor.

24. The combination as claimed in claim 23 wherein the plate is provided with means retaining the same in non-rotative engagement with the movable conductor.

25. In circuit control apparatus, a supporting member, a pair of relatively movable cooperable contact arms carried by said supporting member, each of said arms being under stress for movement relative to said supporting member and to each other, and one of said arms having a portion extending beyond the place of Contact, a fusible member carried by said extending portion and serving. to hold said arms against relative movement, and means electrically insulating said fusible member from said extending portion.

26. The combination as claimed in claim 25 wherein the fusible member is removably mounted on said extending portion.

27. The combination as claimed in claim 25 wherein the fusible member is slidingly and removably mounted on one of said contact arms.

28. In circuit control apparatus, a hollow supporting member having a tubular end portion of insulating material, cooperable contact arms fixed in said hollow member and extending in laterally spaced relation into said tubular1 portion for cooperable electrical engagement, one of said arms being under stress for movement relative to the other of said arms, a fusible member carried by said one arm and retaining the same against movement relative to the other of said arms, and means electrically insulating said fusible member from said one arm.

29. The combination as claimed in claim 28 wherein the arms are each under stress for relative movement with respect to each other and with respect to said supporting member and are held against movement under such stress by said fusible member.

30. In circuit control apparatus, a pair of plates, fusible means interposed between and holding said plates in facewise engagement, supporting members tensioned for movement relvative to each other, means on said plates detachably securing said plates to 5said members thereby to hold said members in relatively xed relation, and means electrically insulating one of said plates from its supporting member.

FREDERICK D. AUSTIN. 

